Vehicle doors occasionally include electro-mechanical cinching assemblies to fully close or "cinch" a door from a partially-latched position (i.e. secondary) to a fully-latched position (i.e. primary). These cinching assemblies are useful on van doors, for example. There are several ways to effect cinching. It can be done, for example, as part of a power sliding door operation with a power sliding door mechanism. One example of this is shown in U.S. Pat. No. 5,138,795 to Compeau et al. Cinching can also be done with a cinching mechanism that has the sole purpose of cinching the door from the secondary position to the primary position regardless of how the door came to be in the secondary position (e.g. through manual or power means).
In operation, a controller disposed on the vehicle senses when the door is in the secondary position. When this happens, the controller initiates cinching by activating some type of cable drive. The cable drive pulls on the cable, which in turn drives the door from the secondary position to the primary position.
In the ideal situation, the cable drive exerts a force on the cable that falls within a predetermined normal operating range for the cable and the vehicle. But it is possible to have a condition where the cable drive must exert an unusually strong force on the cable in order to fully cinch the door. This can happen under several different circumstances including, for example, the case where the door trim is not properly positioned. There are various reasons why one desires to have the cable force necessary to cinch the door below a certain level. For example, if the vehicle's battery voltage dips down somewhat, it may not have sufficient voltage to the cinch the door. Also, because the cable's life is inversely related to the forces acting on it, one wants to ensure that the forces are not too high.
Until now, there has been no easy way to test the force acting on a given vehicle's cinching cable without disassembling the vehicle to some extent.